This application claims priority under 35 U.S.C. xc2xa7119 to Patent Application Serial No. 0104158-1 filed in Sweden on Dec. 7, 2001.
1. Area of the Invention
The present invention relates to a tool for milling, a milling body and method for milling, wherein cutting inserts are mounted in respective pockets spaced apart around an outer periphery of a rotary milling body.
2. Prior Art
At milling, the principle for metal machining comprises a coordinated motion of a rotary multi-edged tool relative to a rectilinearly fed work piece. Alternatively the tool can be fed towards the work piece in substantially any direction. The milling tool has several cutting edges and each cutting edge removes a certain amount of metal.
At face milling, the machining is primarily done by the cutting edges at the circumferential periphery of the tool, but to some extent also by the minor cutting edges at the axial end surface of the tool. The cutting depth in the radial direction is determined by how deeply the cutting edges cut at the periphery. The minor cutting edges at the end surface of the tool generate the finished surface. A drawback of a prior face-milling cutter is that only a little part of each cutting edge is active to perform the cutting (i.e., to absorb the reactive forces), so the wear during face milling is rapid (resulting in shorter life span) as well as frequently requiring longer time of engagement with the work piece. In addition, frequently edge breakages occur at machining of brittle work pieces.
One object of the invention is to provide an improved milling tool for face milling.
One further object of the present invention is to provide a milling tool for face milling at which each cutting edge of a cutting insert can be better utilized.
Another object of the present invention is to provide a milling tool for face milling at which the cutting inserts obtain a longer life span.
Still another object of the present invention is to provide a milling tool for face milling that requires relatively few passes over the work piece for each cutting insert.
Still another object of the present invention is to provide a milling tool and a method for face milling, wherein the bordering edges of the work piece break less frequently.
Still another object of the present invention is to provide a milling tool for face milling at which certain machining data, at least the axial feed, are predetermined by the geometry of the tool.
Still another object of the present invention is to provide a milling tool for face milling at which the resultant cutting forces favors machining in weak machines as well as simplifies fixing of the work piece.
These and other objects have been achieved by a tool for face milling comprising a milling body which defines an axis of rotation and an axial end surface. The tool also comprises a plurality of cutting inserts carried by the body. The body includes circumferentially spaced pockets in which respective inserts are mounted. Each pocket comprises at least one base surface. Each insert has at least one cutting edge. The milling tool is arranged to cut a work piece substantially in the axial direction which is perpendicular to a feed direction.
Another aspect of the invention relates to a milling body for a milling tool which comprises a plurality of pockets adapted to receive respective cutting inserts. Each pocket includes at least one base surface. The body defines an axis of rotation. The pockets are arranged along at least one path extending helically with respect to the rotational axis. The path forms a pitch angle relative to a plane extending perpendicularly to the rotational axis.
Another aspect of the invention relates to a method of milling a work piece utilizing a milling tool which comprises a milling body and a plurality of cutting inserts carried by the body. The body defines an axis of rotation and includes circumferentially spaced pockets in which respective inserts are mounted. Each pocket comprises at least one base surface. Each insert has at least one cutting edge. The method comprises the steps of rotating the body about the axis while producing a relative feed between the body and the work piece in a direction perpendicular to the axis, and machining the work piece substantially in the axial direction.